cells
This SWELL Protein Keeps Cells in Shape
Posted on by Dr. Francis Collins
Caption: A human cell expressing both the SWELL1 (red) and green fluorescent protein. The red dots reveal the location of SWELL1 on the cell surface.
Credit: Zhaozhu Qiu, The Scripps Research Institute, La Jolla, CA
Anyone who’s taken part in a water balloon fight knows what happens when you fill a balloon with too much water—it bursts. Now, consider that most of our cells are essentially water balloons: a thin membrane envelope containing a mixture that’s mostly water along with some salts, proteins, lipids, carbohydrates, and nucleic acids. Given that the average adult’s body is about 60% water, what keeps our cells from overfilling and exploding?
A few years ago, Zhaozhu Qiu, a postdoctoral fellow in Ardem Patapoutian’s lab at Scripps Research Institute in La Jolla, CA, decided to dig into the molecular details of how cells are able to sense their volume and adjust their shapes accordingly. It’s long been known that, when cells are placed in low-salt solutions, water tends to flow into them, causing them to swell—sometimes to the verge of bursting. Scientists determined, about 30 years ago, that, when this occurs, channels in the cell membrane open and the cells release chloride and other molecules, such as amino acids: a process that drives out the excess water and returns cells to their normal size [1].
Proteins Park Free in this Helix
Posted on by Dr. Francis Collins
Caption: Protein-making factories in cells resemble a helical parking garage.
Credit: Cell, Terasaki et al.
I simply couldn’t resist sharing this image with you, even though the NIH didn’t fund the research. What you see in this picture is a structure called the endoplasmic reticulum (ER)—a protein-producing factory that is present in every single cell in your body. The little nubs on the surface of this membranous structure are ribosomes—they produce the proteins that are then modified in the ER.
The Beauty of Recycling
Posted on by Dr. Francis Collins
Novel proteasome regulation image by Sigi Benjamin-Hong, Strang Laboratory of Apoptosis and Cancer Biology.
All cells recycle. Here, we see actin filaments (red) direct unwanted (malformed, damaged, or toxic) proteins to proteasomes (green). In these barrel-shaped compartments, proteins are chopped up into their basic building blocks, called amino acids, and recycled to make new healthy proteins.
Why We’re So Excited About Stem Cells
Posted on by Dr. Francis Collins
Certainly – as you can see here – stem cells are spectacularly beautiful. But they also hold spectacular promise for medicine. That’s why I immediately expressed my enthusiasm for Monday’s Supreme Court ruling that effectively enables NIH to continue conducting and funding responsible, scientifically worthy stem cell research.
There are many kinds of stem cells. This is a picture of induced pluripotent stem cells – or, iPS cells. Investigators have recently begun using iPS cells to model several neurological diseases – including Parkinson’s. The cells here have been treated with growth factors that coax them into becoming the dopamine producing (dopaminergic) neurons lost in Parkinson’s. The colorized markers indicate the presence of three proteins found within dopaminergic neurons: (1) the enzyme needed to produce dopamine (tyrosine hydroxylase, in blue), (2) a structural protein specific to neurons (Type III beta-tubulin, in green), and (3) a gene regulatory protein needed in dopaminergic neurons (FOXA2, in red). The color-mixing in some cells indicates that all three proteins are present – confirming that these cells are on their way to becoming dopaminergic neurons.
Today’s image is more than just a pretty picture. It’s a window into the ways that disease affects the body – and possibly the ways we might counter those affects. The NIH/NINDS web site has more information about how iPS cells are being used to study Parkinson’s and other neurological disorders.
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